Electron emission device and electron emission display using the same

Abstract

An electron emission device includes a substrate with an effective area and a pad area placed external to the effective area. Cathode electrodes are formed on the substrate. Electron emission regions are formed at the cathode electrodes within the effective area. Gate electrodes are separately insulated from the cathode electrodes by interposing an insulating layer, and have opening portions to expose the electron emission regions. The respective gate electrodes have an effective portion located at the effective area with a first line width, and a pad portion located at the pad area with a second line width. When the line width subtracted from the first line width by the whole line width of the opening portions placed in the width direction of the effective portion is defined as an effective line width, the second line width is established to be larger than the effective line width.

1 . An electron emission device comprising: 
 a substrate with an effective area and a pad area placed external to the effective area;    cathode electrodes formed on the substrate;    electron emission regions formed at the cathode electrodes within the effective area; and    gate electrodes separately insulated from the cathode electrodes by an interposed insulating layer and the gate electrode and the interposed insulating layer having corresponding opening portions to expose the electron emission regions,    wherein each gate electrode has an effective portion located at the effective area with a first line width and a pad portion located at the pad area with a second line width, and    wherein when a line width subtracted from the first line width by the whole line width of the opening portions placed in the width direction of the effective portion is defined as an effective line width, the second line width is established to be larger than the effective line width.    
   
   
       2 . The electron emission device of  claim 1 , wherein the gate electrodes to satisfy the following condition:  
         P 2≧( P 1 +P 3)/2  wherein P1 indicates the first line width, P2 indicates the second line width, and P3 indicates the effective line width.    
   
   
       3 . The electron emission device of  claim 1 , wherein the gate electrode further comprises a variable width portion disposed between the effective portion and the pad portion.  
   
   
       4 . The electron emission device of  claim 3 , wherein the variable width portion is gradually increased in width from the pad portion toward the effective portion.  
   
   
       5 . The electron emission device of  claim 1 , further comprising a focusing electrode placed over the gate electrodes such that the focusing electrode is insulated from the gate electrodes.  
   
   
       6 . The electron emission device of  claim 1  wherein the electron emission regions comprise at least one material selected from the group consisting of carbon nanotubes (CNTs), graphite, graphite nanofiber, diamond, diamond-like carbon (DLC), C 60 , and silicon nanowire.  
   
   
       7 . An electron emission display comprising: 
 an electron emission device, comprising: 
 a substrate with an effective area and a pad area placed external to the effective area,  
 cathode electrodes formed on the substrate,  
 electron emission regions formed at the cathode electrodes within the effective area, and  
 gate electrodes separately insulated from the cathode electrodes by an interposed insulating layer and the gate electrodes and the interposed insulating layer having corresponding opening portions to expose the electron emission regions, wherein the respective gate electrodes have an effective portion located at the effective area with a first line width, and a pad portion located at the pad area with a second line width, wherein when the line width subtracted from the first line width by the whole line width of the opening portions placed in the width direction of the effective portion is defined as an effective line width, the second line width is established to be larger than the effective line width;  
   a counter substrate facing the substrate;    phosphor layers formed on a surface of the counter substrate; and    an anode electrode formed on a surface of the phosphor layers.    
   
   
       8 . The electron emission display of  claim 7 , wherein the gate electrodes to satisfy the following condition:  
         P 2≧( P 1 +P 3)/2  wherein P1 indicates the first line width, P2 indicates the second line width, and P3 indicates the effective line width.    
   
   
       9 . The electron emission display of  claim 8 , wherein the effective line width, P3 is expressed by:  
     
       
         
           
             
               P 
               ⁢ 
               
                   
               
               ⁢ 
               3 
             
             = 
             
               
                 p 
                 ⁢ 
                 
                     
                 
                 ⁢ 
                 1 
               
               + 
               
                 
                   ∑ 
                   
                     i 
                     = 
                     2 
                   
                   
                     n 
                     - 
                     1 
                   
                 
                 ⁢ 
                 
                   p 
                   i 
                 
               
               + 
               
                 p 
                 n 
               
             
           
         
       
       when the number of openings is 4 or greater, wherein p1 and p n  are the distances between the outermost opening portions and the ends of the effective portion sided therewith, respectively, pi are distances between the openings, and n is the number of openings wherein p1 to p n  are all measured along a line passing over centers of all the openings.  
     
   
   
       10 . The electron emission display of  claim 7 , wherein the gate electrode further comprises a variable width portion disposed between the effective portion and the pad portion.  
   
   
       11 . The electron emission display of  claim 10 , wherein the variable width portion is gradually increased in width from the pad portion toward the effective portion.  
   
   
       12 . The electron emission display of  claim 7 , further comprising a focusing electrode placed over the gate electrodes such that the focusing electrode is insulated from the gate electrodes.  
   
   
       13 . The electron emission display of  claim 7 , wherein the electron emission regions comprise at least one material selected from the group consisting of carbon nanotubes (CNTs), graphite, graphite nanofiber, diamond, diamond-like carbon (DLC), C 60 , and silicon nanowire.  
   
   
       14 . An electron emission device comprising: 
 cathode electrodes formed on a substrate to carry a voltage;    electron emission regions formed at the cathode electrodes within an effective area;    a gate electrode to emit electrons from the electron emission regions, wherein the line width of the gate electrode is greater in a pad area than an effective line width of the gate electrode in the effective area, to lower a resistance of the gate electrode in the pad area below a resistance of the gate electrode in the effective area.    
   
   
       15 . The electron emission device of  claim 14 , wherein the gate electrode comprises openings to expose the electron emission regions and the effective line width of the gate electrode in the effective area is a difference between the line width of the gate electrode in the effective area and a total line width of opening portions placed in the width direction of the effective portion.  
   
   
       16 . The electron emission device of  claim 14 , wherein the gate electrode further comprises a variable line width portion comprising a gradually increased line width to connect the gate electrode in the pad area to the gate electrode in the effective area.  
   
   
       17 . An electron emission display, comprising: 
 the electron emission device of  claim 14;     an external circuit connected to the gate electrode at the pad area to supply a driving voltage to the electron emission device;    a counter substrate facing the substrate;    phosphor layers formed on a surface of the counter substrate to emit light when excited by the emitted electrons; and    an anode electrode formed on a surface of the phosphor layers to accelerate the emitted electrons.    
   
   
       18 . The electron emission display of  claim 17 , wherein the phosphor layers further comprise red, green, and blue phosphors spaced apart from each other by a black layer disposed between the respective phosphor layers.  
   
   
       19 . The electron emission display of  claim 17 , wherein the anode electrode comprises an aluminum metallic material.